FIGURE 6.

Characterization of FV-B8-BR variants. Panel A, specific clotting activities of FV/FV(a) derivatives before (white bars) or after treatment with thrombin (black bars) were determined by a FV-specific PT-based clotting assay as described under “Experimental Procedures.” The data are the means ± S.D. of at least three experiments. FV-810 and PD-FV are for reference and are from Fig. 3A. Panels B and C, reaction mixtures containing 50 μm PCPS, 3.0 μm DAPA, 1.4 μm prothrombin, and 0.1 nm FV derivatives were incubated for 5 min at 25 °C. The reaction was initiated with 1.0 nm FXa, and thrombin generation was monitored as described under “Experimental procedures.” The symbols represent the following: FV-810 (▴), FV-B8-BR1 (▾), FV-B8-BR2 (*), FVB8-BR3 (⎔), PD-FV (□). The lines represent a linear fit of the data, except for FV-B8-BR3 and PD-FV in panel B, which results from a polynomial fit. The data are the means ± S.D. of 2–4 similar experiments.